This invention pertains to the field of installing traction-enhancing chains on pneumatic tires of wheeled vehicles, for use on mud, snow, and ice surfaces.
The advantages of tire chains have been known for many years. When needed, tire chains provide enhanced traction on mud, snow, and ice surfaces, both for moving and for stopping the vehicle. Also, tire chains are relatively inexpensive and do not affect vehicle ride, handling, fuel economy, or performance when they are not necessary, which is at least 99 percent of the time for 99 percent of the people in the United States.
Also known are the disadvantages of tire chains, which, assuming well designed chains are properly selected for a given vehicle, tend to fall into three categories. The first category is installation. The disadvantages within this category include the considerable time required for installation and the physical difficulty and discomfort involved, often under adverse weather conditions, darkness, or stress. They may further include, depending upon whether a jack is employed, safety considerations or the need to re-adjust the chains after the vehicle has been driven. These disadvantages are described further in the patents identified below and in other patents in U.S. Patent and Trademark Office subclasses 152/213R and 81/15.8. The second category of disadvantages is operation of the vehicle after the chains have been installed. These disadvantages include chain wear and breakage, limitations on vehicle speed, vibration and accelerated wear of the vehicle, possible damage to the vehicle resulting from breakage of worn chains, and damage to the pavement. These disadvantages are greatly amplified by operation of the vehicle on bare pavement. The third category is removal of the chains from the tire.
These three categories of disadvantages are directly related, in that solutions to installation and removal problems ameliorate problems during vehicle operation. This is because, as a practical matter, the ability to install and remove tire chains quickly and easily enables the user to remove them as soon as the vehicle reaches bare pavement, knowing that the tire chains can be readily re-installed as soon as (or if) they are needed again. Theoretically, perfect solutions to the installation problems and removal problems would eliminate nearly all of the operating problems. That is, if tire chains could be installed instantly by a mere snap of the driver""s fingers immediately before serious snow or ice are encountered, and removed in the same manner when no longer needed, their above-mentioned operating disadvantages would disappear.
Some solutions involve ramps having spaced lateral grooves. After the tire chain is laid out with its cross chains lying loosely in the grooves, the vehicle is driven onto the ramp. The grooves allow the cross chains to be adjusted to positions where the necessary degree of tension can be attained before the ends of the chain are connected. See, for example, Garey U.S. Pat. No. 2,022,804. Such drive-on ramps are most efficiently used in pairs, one pair for each pair of drive wheels. A problem presented by ramps is the difficulty of stopping the vehicle at the desired position on the ramp. One approach to solving this problem is to provide a stop for the wheel, as disclosed for example in Rhoads et al U.S. Pat. No. 2,604,802. This approach is not always effective, because under actual conditions it is difficult for the driver to feel the stop through the vehicle and distinguish it from other bumps, and he or she may drive the vehicle over the stop. A better approach is to signal the driver that the vehicle has reached the correct position, as taught for example by Masegian U.S. Pat. No. 4,194,724. Another significant improvement in ramps was the provision for storage with the chain oriented on the ramp, which Planz U.S. Pat. No. 3,893,500, xe2x80x9cChain Caddyxe2x80x9d, accomplished by upstanding edges on the ramp.
Other solutions to the problems of installing tire chains involve tools for engaging end elements of the chain. An examples is Nakata U.S. Pat. No. 4,210,036 (hinged elongated rod). Other examples are Dalaba U.S. Pat. No. 4,703,675 and Stiles U.S. Pat. No. 1,914,760 (U-shaped tools to hold end of chain to tire during rotation to wind chain on tire). U-shaped tools have also been used with tire chains for other purposes, as shown for example by Krennwallner German patent 155,387 (tensioning device).
Other solutions avoid the use of a jack or a ramp by applying a tire chain configured so that its ends can be connected with the cross chains nearest the ends outside the footprint of the tire and with no chain beneath the footprint. This involves a compromise between ideal spacing between cross chains and achieving proper tension, and usually requires driving and stopping the vehicle after the tire chains have been installed and re-adjusting them. Also, a popular way of accomplishing this installation is to use a large hoop as an integral part of each tire chain. The hoop makes the tire chain difficult to store and handle and may require extensive manipulation of the tire chain under and on the sidewalls of the tire. The hoop also makes removal of the tire chain more difficult.
Despite the large number of patents directed to solving the problems of installing a tire chain, there remains a need for a single system which is capable of performing all of the following functions:
(a) storing an oriented tire chain having conventional side chains;
(b) handling and positioning the ramp and chain with respect to the tire before the vehicle is driven;
(c) correctly positioning the tire with respect to the chain when the vehicle is stopped;
(d) placing the chain, untwisted, on the tire in approximately the correct position;
(e) adjusting and tensioning the chain;
(f) ascertaining the location of the fastening elements at the end of the chain; and
(g) positively connecting those elements.
Such a system should accomplish the foregoing in the following manner:
(h) without fumbling or unsuccessful attempts by the user;
(i) while minimizing or eliminating contact of the user""s hands with the chain, or the user""s body with the ground or snow;
(j) without requiring exceptional mechanical ability, strength, or dexterity on the part of the user;
(k) simply, reliably, and inexpensively; and
(l) quickly.
Generally speaking, the last requirement, xe2x80x9cquicklyxe2x80x9d, embraces many of the other requirements and will be the major factor determining the efficacy of the system.
The present invention is a drive-on system for installing tire chains, including storage and handling, on a pneumatic tire mounted on a vehicle wheel. Its object is to meet the need described above in the manner described above.
The inventive system utilizes a U-shaped installation tool having arms extending outwardly from opposite ends of a transverse body member or handle. Movable clasp mechanisms at the ends of the arms releasably but securely engage an end element at one end of each side chain. Each clasp mechanism comprises coacting members which are relatively movable to both a confining configuration, in which the clasp mechanism will confine the element, and a releasing configuration, in which it will release the element. The arrangement of the elements of the tool corresponds roughly to the anatomy of a hardshell crab.
The system also utilizes a tray-like device in which the tire chain and the tool are arranged, and may be stored, in a partially laid-out orientation prior to installation. This device, which performs the function of the ramps and chain caddy referred to above, will be referred to hereinafter as an xe2x80x9cinstallation trayxe2x80x9d or xe2x80x9ctrayxe2x80x9d. The installation tray has longitudinal channels and transverse channels for holding laid-out side chains and cross chains, respectively, and a well for holding side chains and cross chains which are not laid out. The installation tray also has a compartment adjacent the well for holding the tool and protecting it from damage due to the weight of the vehicle.
The method of installing the tire chain is as follows. The untwisted tire chain is arranged in the tray with the tool connected to it, as described above. The vehicle is driven onto the tray and stopped when the vehicle is in a predetermined, optimum position with respect to the tray and chain. Holding the handle, the user picks up the tool and draws it, with one end of the tire chain trailing it, upward and circumferentially around the tire. With the tool straddling the tire so that its handle bridges the tread of the tire and its arms extend along the opposite sidewalls, the tire chain is disposed and tensioned substantially in its correct position on the tire. The fastening element at the other, free end of each side chain is then brought up and connected to the mating fastening element. The connection of the side chain elements on the inner sidewall may be made while the tool is still connected to the fastening element, which enables the arm of the tool on the inner sidewall to be used to guide the free element into contact and connection with the element connected to the tool. In most cases this eliminates the need for the user to see the two elements being connected and the need to hold the two elements with both hands simultaneously, so that the user does not need to lie on the ground. After the tool is disconnected from the chain, the vehicle is driven off the tray.
The system according to the invention may include additional features. The inner arm of the tool may have flanges defining a channel for guiding the free fastening element into proximity and contact with the fastening element held by that arm. An inclined ramp-like surface may be disposed in that channel. The tray may have slots for locating and restraining the free fastening elements, and stacking lugs and recesses to permit a plurality of trays to be stacked during storage. A device may be provided in a recess in the tray to sense the position of the tire and initiate a signal to stop the vehicle. The position of the signal-initiating device relative to the transverse channels in the tray may be adjustable. Preferably the signal issues when, and only when, the tire is positioned within a predetermined theoretical zone defined by boundaries spaced along the longitudinal axis of the tray, so that the device is able to sense and signal the stopped position of the tire as well as the position of the tire while it is still moving. The chain elements held by the arms of the tool may be released therefrom by the action of a readily accessible latch or similar locking device under the control of and actuated by the user. Force for opening the claws of the tool may be applied to the open latch. The handle of the tool may be articulated to permit the claws of the two arms, and the elements of the chain they hold, to be brought close to each other. The tool may have features which enable it to be easily adapted and used for tires of different sizes.